- Joined Jun 10, 2020
I bought a used Yamaha digital piano P-60. It has the following severe issues:
- All keys and the control buttons don't work randomly. "Not working" means when I press down a key, no sound comes out from the speakers.
- It's not about any specific key. It happens to random key. Sometimes all keys have no sound.
- Sometimes the Demo button and Voice button don't work either.
- Sometimes the voice changes automatically (e.g. from piano sound to organ sound). It's like the Voice button is pressed by a ghost.
- It can play demo for hours without any problem. Looks like the main chip is good.
- Volume control (slider) works well.
- No key has exceptionally high or low sound.
- Hypothesis 1: the power adapter is faulty. I tried another power adapter. No change.
- Hypothesis 2: there is loose connector. I opened the piano several times but didn't see any loose connector. I unplugged some connectors and plugged them again. No difference.
- Hypothesis 3: some capacitors are faulty. I didn't see any bulging capacitors. I used an auto-range multi meter to measure some capacitors, but the values did not make sense. Later I knew it's hard to measure on-board capacitor's capacity with the normal multi meter. I searched the internet and watched some videos. I still believe they may be something wrong with the capacitors.